The present invention relates to an equipment for producing a corrugate fin, which is used for a heat exchanger.
Corrugate fins are used in, for example, air conditioners for vehicles. An example of the corrugate fins is shown in FIGS. 21 and 22. The corrugate fin 10 is made of a thin metal plate having a plurality of corrugated sections 12, which are formed like waves. The corrugate fin 10 is provided in a tube. By using the corrugate fin 10, heat exchange with a heat medium running through the tube can be effectively performed.
When the corrugate fin 10 is produced, the metal plate must be drawn, so all of the corrugated sections 12 cannot be formed at a time. The corrugated sections 12 must be formed in order.
Conventionally, the corrugated sections 12 are formed by a press machine. However, the press machine forms one corrugated section 12 by one press action. Therefore, production efficiency is low.
To solve the problem of the low production efficiency, a plurality of gear-shaped forming rolls, which clamp a metal plate, are used. The metal plate is fed to the forming rolls in series so as to form the corrugated sections 12 in order (see Japanese Patent Gazette No. 2004-223686).
Production efficiency of the method disclosed in Japanese Patent Gazette No. 2004-223686 is higher than that of the conventional method, in which one corrugated section is produced by one press action. However, this method can form circular arc corrugated sections, but cannot form rectangular corrugated sections.
Note that, if the feeding direction of the metal plate fed to the forming rolls is parallel to the longitudinal direction of the corrugated section, the rectangular corrugated section can be formed. But, in this method, a half of the rectangular corrugated section is formed by one press action, so a large number of the forming rolls must be required and a production line must be long.
Thus, an equipment having a plurality of punches, which are driven in order so as to form rectangular corrugated sections, was invented (see Japanese Patent Gazette No. 2003-115567). This equipment is a compact size and capable of efficiently producing rectangular corrugated sections. The equipment is capable of forming a plurality of rectangular corrugated sections by one forming action.
The equipment disclosed in Japanese Patent Gazette No. 2003-115567 is capable of shortening the time for producing corrugate fins and reducing production cost.
The equipment disclosed in Japanese Patent Gazette No. 2003-115567 is used for producing corrugate fins for heat sinks of CPUs, so the corrugate fins can be produced by punches, which are horizontally moved by cylinder units. However, corrugate fins for heat exchangers of air conditioners are much larger and must have higher strength, they cannot be produced by horizontally moving punches. Therefore, an equipment, which is capable of forming a plurality of corrugated sections by one closing action of a lower block and an upper block.
Further, the equipment disclosed in Japanese Patent Gazette No. 2003-115567 has a cam for actuating the punches. The cam is horizontally moved in one direction so as to vertically move the punches. The cam firstly contacts one end of each punch, so a pressing force is applied to the one end only. Further, the pressing force is continuously applied in the moving direction of the punch. Namely, the pressing force, which is inclined with respect to the moving direction of the pupnches, is always applied to the punch.
Since the unsymmetrical pressing force is always applied to the punches, the corrugated sections cannot be precisely produced and the punches and a die are unevenly abraded.